Signal or alarm.



No. 669,644. Patented Mar. l2, mm. P. M. JER-RARD. SIGNAL 0B ALARM.

(Application filed Ochi 5, 1900.)

(No Model.)

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NITE STATES PAUL MILLINGTON JERRARD, OF J OHANNESBURG, SOUTH AFRICAN REPUBLIC;

SIGNAL OR ALARM.

$PEGIFIGATION forming part of Letters Patent N 0. 669,644, dated March 12, 1901. Application filed October 5,1900. Serial No. 32,204. \No model.)

To all whom it may concern:

Be it known that 1, PAUL MILLINGTON J EB- RARD, electrical engineer,of Crown Deep Gold Mining Company, Johannesburg, South African Republic, at present of 9 Oourtis Chambers, St. Georges street, Cape Town, Cape Colony, have invented certain new and useful Improvements in Signals or Alarms, of which the following is a specification.

This invention relates chiefly to electrically-operated mine-bells, circuit-closers, telephone-call bells, and like signaling apparatus, but may also be applied to similar apparatus which is operated by other than electric power, (such as a mechanically-operated bell having the hammer or striker inclosed in a box,) which is separated from but connected to a bell or gong by a pin and'vibrating disk; and the improvements consist in the system of and means for externally connecting a bell, gong, or other like instrument to a metal box or case within which is contained and hermetically sealed the working mechanism, includingthe hammer or striker which rings or sounds the bell. The object of this is to provide a hell or signaling instrument which is less liable to be tampered with or put out of order than bells or signaling instruments as hitherto manufactured and known and may safely be placedand used in coal-mines or similar places without fear of its causing an explosion of gas and in any vapor or moisture without fear of the working parts being injuriously affected by the fumes or dampness.

The system or invention will be more easily understood by reference to the accompanying drawings, in which- Figure 1 is a transverse vertical section, and Fig. 2 a. side elevation.

The numeral 1 represents a metal box, (preferably of cast-iron,) shownwith the lid removed. This box is made of suitable shape to fit under the gong or bell 2 and just deep enough to carry the striking mechanism. The hell 2 is rigidly bolted to the box by the nut 3. One side of the box may be made very thin, about one sixty-fourth of an inch only. As this in cast-iron would be impracticable, I prefer to bore a round hole as large as the thickness or depth of the box will allow right through the side of the box. In this hole I solder a neatlyfitting preferably stamped brass (or other suitable metal) disk about one sixty-fourth of an inch thick, which I call the vibrating disk, 4, with a small hole in the center to carry the pin 5. The pin 5 is made of steel wire two inches long and three thirtyseconds of an inch thick, threaded at both ends. One end is screwed into the rim or periphery of the bell and locked there by the nut 6. The other end of the pin is pushed or screwed into the center of the thin portion of the box or vibrating disk 4 and secured there either by lock-nuts and washers 7 or by soldering.

An iron standard or bracket 8, carrying the electromagnet 9 and armature 10, is screwed to the bottom of the box, (calling the lid the t 77) I A terminal post 11, mounted upon a baseplate 12, is screwed to the bottom of the box and carries the usual platinum-tipped contact-screw 14, upon which the armature-spring 13 normally rests.

The hollow bolts 14 are screwed into holes drilled and tapped three-quarters through the thick end of the box. Rubber washers are inserted into these holes before the bolts 14 are put in.

Insulated electric conductors 16 pass from outside through the bolts, washers, and suitable holes in the box and are connected with the magnet and terminals in the usual manner. The bolts 14 are then screwed in and compress the rubber washers 15 until the joints are gas-tight.

A metal lid 19 is made to fit the box neatly and is secured in position by one or more screws or abolt or nut 18. The joint between the box and the lid is packed with a thin layer or band of rubber, red lead, or other suitable packing material.

In operation upon electricity actuating the magnet 9 the armature 10 is attracted and causes the hammer 17 to strike the internal extremity of the pin 5. The blow causes the bell to vibrate or ring, and the center of the disk, with the pin 5, follows the vibrations of the bell Without materially lessening the tone or sounding power of the bell. In order not to confine my invention to this arrangement of parts, as an alternative instead of placing the bell over the box, as before described, containing the striker and mechanism the box may conveniently be secured to the out side of the bell,which arrangement allows the use of a larger box and more powerful magnets or other suitable operating mechanism.

The following parts of the above instrument are old, and I do not claim themnamely, the gong 2, nut 3, bracket 8, magnet 9, armature 10, hammer 1'7, terminal posts 11, armature-springs 13, and gas-tight joint made up of bolts 14 and packing 15and any other well-known and suitable mechanism may be employed instead.

I claim as my invention- 1. A signal or alarm comprising a bell, a hermetically-sealed casing, a rod having one end in contact with said bell and its other end terminating within the hermetically-closed casing, and a hammer or clapper within said casing for striking the end of the rod with means for operating said hammer, substantially as described.

2. In combination, the bell, a hermeticallyclosed casing within the same, a rod having one end rigidly connected to the edge of the bell and its other end terminating within the casing, a hammer or clapper within said casing, and electrically-operated means for vibrating said hammer, substantially as described.

3. In combination, the bell, the hermetically-closed casing having a flexible portion, a rod having one end rigidly connected to the edge of said bell and the other end passed air-tight through said flexible portion, a hammer Within said casing in proximity to the end of said rod, and electrically-actuated means for operating said hammer, substantially as described.

In witness whereof I have hereunto set my hand in presence of two witnesses.

PAUL MILLINGTON JERRARD.

Witnesses: I

W. S. C. STAVSANT, CHAS. H. BROWN. 

